1. Field Of The Invention
This invention describes detergent builder materials which are suitable as partial or total replacements for phosphates or nitrogen-containing builders.
2. Description Of The Art Practices
Detergent builders are used to enhance the activity of the detergent or surfactant material used for cleaning. A detergent product typically contains a surface-active material (surfactant) which is used to lift dirt from the fabrics and to penetrate into the fabrics to remove embedded soil. Typically, these surface-active agents are the sodium salts of anionic materials. As the bulk of heavy-duty detergents are of the anionic nature, there exists an interference in the cleaning mechanism when calcium or magnesium ions (which are present as water hardness or body soil) react with the anion. In the case of body soil, the surfactant will become fixed onto the fabric due to the formation of the insoluble calcium or magnesium salt. The calcium or magnesium cations within the water cause the surfactant to be inactivatedd due to the formation of insoluble salts.
Heavy-duty liquid detergent products have been difficult to formulate utilizing currently available detergent builders. This is most evident as the common detergent builders employed tend to be phosphate salts which precipitate out of a liquid composition when utilized at an effective amount for cleaning. Although heavy-duty liquid detergent products are often formulated with a substantial amount of a nonionic surfactant such as ethoxylated alcohol which is not metal ion sensitive, the ability of calcium and magnesium ions to fix on the soil leads to the desirable inclusion of a detergent builder.
As mentioned previously, phosphate salts such as sodium tripolyphosphate or sodium pyrophosphate have been extensively used. Several states have outlawed the use of phosphorous-containing compounds in detergent products due to the eutrification caused by the presence of the phosphates. Replacements for phosphates as builders in detergent products have included organic nitrogen-containing compounds, carbonates and aluminosilicates. Each of these materials has its own particular negatives associated therewith. For instance, concern has been expressed over the widespread usage of organic nitrogen-containing compounds due to potential carcinogenic effects and their propensity to chelate desirable heavy metal ions in the environment. Carbonates have been widely employed but are generally ineffective as detergent builders as they result in the build-up of scale due to insoluble calcium carbonate formation. Aluminosilicates are insoluble materials commonly used in water softeners. The aluminosilicates are disadvantageous in that, as an insoluble material, they may be retained upon clothing or fabric and may cause excessive wear of washing machine components. The aluminosilicates are also not useful in liquid products due to their insolubility.
It is, therefore, desirable to formulate detergent products containing builders which do not contain nitrogen or phosphorous and which are water-soluble and are biodegradable. It has been reported in an article entitled "Nitrogen-and Phosphorous-Free Strong Sequestering Building", Kemper et al, Tenside Detergents, 12 page 47-51 (1975) that the reaction product of ethylene glycol and dimethyl diazomalonate results in such a compound. While this material avoids the presence of phosphorous or nitrogen in the final product, its preparation requires the handling of hazardous diazo compounds and requires exaggerated temperature and the use of copper as a catalyst to form the desired compound, thereby imparting relatively high costs to the final product. The efficacy of this compound as reported by the authors is rated at about 97% of sodium tripolyphosphate. Other compounds disclosed in the Kemper reference show Builder M (2-oxa-1,1,3-propanetricarboxylic acid) at 93% of sodium tripolyphosphate. A further proposed material 2-oxa-1,3,4-butanetricarboxylic acid (CMOS) is rated at only 90% of sodium tripolyphosphate.
It is further recommended by the present authors that the reader review U.S. Pat. No. 3,692,685, issued to Lamberti et al on Sept. 19, 1972, as well as U.S. Pat. No. 3,128,287, issued to Berg on Apr. 7, 1964. Further disclosures of carboxylic acid materials are found in U.S. Pat. No. 4,021,376 issued to Lamberti et al on May 3, 1977.
German Pat. No. 2,147,780, published on Mar. 29, 1973, to Kandler et al and German Pat. No. 2,408,591, published on Sept. 4, 1975, to Borggrefe et al, also concern the general subject matter of the present invention. The article of Crutchfield entitled "Organic Builders: A Review of Worldwide Efforts to Find Organic Replacements for Detergent Phosphates" published in the JAOCS 55, pages 58-65 (1978), and the Matzner et al article entitled "Organic Builder Salts as Replacements for Sodium Tripolyphosphate (I)" in Tenside Detergents, 10, pages 119-125 and 239-245 (1973) also provide useful information concerning the general scope of the present invention. Further information on detergent products is found in Stubbs et al U.S. Pat. No. 4,017,541 issued Apr. 12, 1977 and Borggrefe's U.S. Pat. Nos. 4,002,676 and 4,219,672 issued Jan. 11, 1977 and Aug. 26, 1980 respectively.
To the extent that each of the foregoing references are pertinent to this disclosure, they are herein incorporated by reference.
The present invention deals with the formation of a detergent builder from readily available materials which do not contain phosphorous or nitrogen. The new builder is biodegradable, is readily soluble in water and has superior detergent builder capabilities over known related compounds.
Throughout the specification and claims, percentages and ratios are by weight, pressures are in atmospheres and temperatures are in degrees Celsius unless otherwise indicated.